Currently, when editing shader parameter overrides in the "Write To Materials", if you attempt to write the same material property to the same renderer, if enabled it will only display one of them and won't be predictable as to which.

While there is a valid case to allow it to happen from multiple receivers to the same mesh (when only one is enabled at a time) this can cause unpredictable behaviour if you're not looking out for it.

It would be beneficial to, in the info box on the receiver, flag up if you attempt to write the same property to the same mesh over multiple receivers as potentially unpredictable and warn you should do this "only if you know what you are doing".